Examkin

Question

Difficulty: MediumStrengthening Arguments

Six months ago, a maritime freight company equipped its fleet of cargo ships with automated wind sails designed to reduce diesel fuel consumption. Over this period, the fleet recorded only a 2 percent drop in fuel consumption per nautical mile, far short of the manufacturer's advertised 10 percent reduction. Nevertheless, the company's logistics analysts conclude that the wind sails successfully provided fuel savings consistent with expectations.

Which of the following, if true, most strongly supports the logistics analysts' conclusion?

  1. A
    Several competing shipping lines operating on identical maritime routes without wind sails reported a 5 percent decrease in fuel consumption over the same six-month period due to unusually favorable ocean currents.
  2. During the past six months, new maritime regulations required the fleet to increase its average cargo weight per trip by 25 percent, an adjustment that typically increases fuel consumption per nautical mile by at least 8 percent.Answer
  3. C
    The purchase and installation costs of the wind sails are projected to be fully recovered through reduced operational expenses over the next four years.
  4. D
    The manufacturer of the wind sails recently released an upgraded control algorithm that optimizes sail positioning based on real-time satellite wind forecasts.
  5. E
    The shipping company's overall operational expenditures decreased during the trial period primarily due to a sharp drop in global crude oil prices.

Answer

The argument is most strongly supported by the statement indicating that increased cargo weight during the trial period would normally have raised fuel consumption by at least 8 percent.
The correct answer demonstrates that an unmentioned confounding factor—a 25 percent increase in cargo weight—would normally have increased fuel consumption by at least 8 percent per nautical mile during the trial period. If fuel consumption would have increased to 108 percent of baseline without the sails, but instead decreased to 98 percent (a 2 percent overall drop), the sails actually achieved an effective savings of approximately 10 percent, perfectly matching the original expectations.

Step-by-Step Solution

1
Identify the conclusion and premises of the argument.
Premise: The fleet saw only a 2% reduction in fuel consumption per nautical mile instead of the expected 10%. Conclusion: The wind sails were nevertheless effective and delivered fuel savings consistent with expectations.
Understanding the discrepancy between the observed 2% reduction and the expected 10% reduction is necessary to find information that resolves the gap.
2
Determine what type of evidence is needed to strengthen the conclusion.
Evidence showing that external factors increased baseline fuel usage during the trial period would account for the missing savings percentage.
If baseline fuel consumption would have risen in the absence of the sails, the observed 2% net drop represents a much larger gross savings than it appears.
3
Evaluate the choices to find the statement that accounts for this baseline change.
The option stating that heavier cargo loads would normally increase fuel consumption by 8% establishes that without sails, fuel usage would have been 108% of normal. A net drop to 98% means the sails achieved a 10% effective reduction.
This confirms the analysts' conclusion by establishing that the sails performed exactly as expected once confounding variables are controlled.

Key Concept

Strengthening Causal and Evaluative Arguments by Controlling Confounding Variables
Rate this question

Topics

Strengthening Arguments

More questions from this topic